1. Field of the Invention
The present invention relates to a one way clutch for use as a backstop part in a torque converter of vehicles such as automobiles or the like, and more particularly, it relates to a one way clutch having a bearing function. The present invention also relates to a stator assembly including such a one way clutch.
2. Description of the Related Art
In general, a one way clutch is used to transmit or interrupt a power along a single direction in a power transmission mechanism of an automobile or the like. Some of such one way clutches are used in a stator of a torque converter. As to this one way clutch, an outer ring of the one way clutch is pressed or key-fitted into a stator wheel, whereby the one way clutch is disposed integrally in the stator. On opposite sides of the one way clutch, bearings which receive a radial load are arranged in many cases. Such an example is disclosed in, for example, Japanese Patent Application Laid-Open No. 2009-299862 and Japanese Patent Application Laid-Open No. 2009-299860.
FIG. 4 is an axial sectional view of a one way clutch 130 schematically showing the above conventional technology. The one way clutch 130 comprising an outer race 110 disposed integrally in a stator wheel 190 of a torque converter and an inner race 120 includes a clutch portion 180 interposed between the outer and inner races and having a sprag.
On the opposite sides of the one way clutch 130 in an axial direction, there are arranged two bearings 140 and 150 which receive the radial load. The bearings 140 and 150 are supported by thrust bearings 160. In consequence, a total width W3 of a stator assembly 200 containing the one way clutch 130 in the axial direction becomes large.
However, in the conventional one way clutch typically disclosed in Japanese Patent Application Laid-Open No. 2009-299862 and Japanese Patent Application Laid-Open No. 2009-299860 as described above, the bearings at opposite ends in the axial direction are supported by aluminum bushes, the thrust bearings or the like, and hence the axial length of the stator assembly 200 cannot be shortened.
In recent years, miniaturization and lightening of devices mounted on a vehicle have strictly been required, and there have further been demanded the shortening of the axial length (the total width) of the stator assembly including the one way clutch or the lightening by simplification of peripheral parts. However, the conventional one way clutch cannot always satisfy the demand.